Technical Field
[0001] The present invention relates to an aircraft interior panel material and a method
of manufacturing the same.
Background Art
[0002] Interior components of an aircraft, such as aircraft lavatory units, galleys, luggage
compartments, are constituted by panel members. While it is a given that interior
panel members for an aircraft, such as floor panels, wall panels, and ceiling panels
are required to be strong and rigid, flame retardancy and weight reduction have also
been demanded. Such a panel member having a configuration in which a surface member
including fiber-reinforced composite material is adhered to both surfaces of a honeycomb
core including aramid fiber, glass fiber, aluminum, or the like is known (see Patent
Document 1).
Citation List
Patent Literature
[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No.
2000-238154A
Summary of Invention
Technical Problem
[0004] However, honeycomb cores tend to be expensive and must be incinerated or buried upon
disposal. As such there is room for improvement to reduce the environmental impact
of honeycomb cores.
In light of the above, an object of the present invention is to provide an aircraft
interior panel material and a method of manufacturing the same which both satisfy
cost reduction, strength, rigidity, flame retardancy, and weight reduction requirements
and can assist in environmental impact reduction.
Solution to Problem
[0005] To achieve the object described above, the invention of claim 1 is an aircraft interior
panel material including a core member; and surface members including fiber-reinforced
composite material, the surface members being attached to both surfaces of the core
member. In such an aircraft interior panel material, the core member includes a plate
member composed of balsa wood, and both surfaces of the plate member are impregnated
with a flame retardant.
According to the invention of claim 2, each of the surfaces of the plate member is
provided with a plurality of surface-area increasing components recessed from the
surface and configured to increase the surface area of the surface.
[0006] According to the invention of claim 3, the surface-area increasing components are
constituted by any one of: a hole passing through the plate member in the thickness
direction thereof, a recessed portion with a closed bottom that has depth in the thickness
direction of the plate member, and grooves formed extending in both surfaces of the
plate member in the thickness direction of the plate member; or a combination thereof.
The invention of claim 4 is a method of manufacturing an aircraft interior panel material
provided with surface members including fiber-reinforced composite material attached
to both surfaces of a core member, wherein both surfaces of a plate member to be used
as the core member are impregnated with flame retardant.
[0007] The invention of claim 5 includes disposing a plurality of surface-area increasing
components in each of the surfaces of the plate member prior to impregnation of the
surfaces of the plate member with the flame retardant, the surface-area increasing
components being recessed from the surface and configured to increase the surface
area of the surface.
According to the invention of claim 6, the attaching of the surface members to both
surfaces of the core member is performed by:
upon the surface members being layered on both surfaces of the core member, melting
resin with which the surface members have been impregnated by applying pressure and
heat to bond the resin to the surfaces of the plate member and the surface-area increasing
components. According to the invention of claim 7, the impregnation of the surfaces
of the plate member with the flame retardant is performed by:
upon immersing the plate member in the flame retardant and applying a pressure larger
than a pressure at a depth where the plate member is immersed to the plate member,
maintaining this state for a predetermined period of time.
Advantageous Effect of Invention
[0008] According to the invention of claim 1, because balsa wood, which is inexpensive and
easy to handle in terms of disposal and recycling, is used as the core member, advantages
in terms of requirements of cost reduction, strength, rigidity, flame retardancy,
and weight reduction being satisfied and environmental impact being reduced are obtained.
According to the invention of claim 2, because the surface-area increasing components
are provided, the surface area of the plate member to be impregnated with the flame
retardant is increased and advantages in terms of securing greater flame retardancy
are obtained. In addition, advantages in terms of further weight reduction of the
interior components of an aircraft are obtained by reducing the weight of the aircraft
interior panel material.
According to the invention of claim 3, because the aircraft interior panel material
can be formed with easily machined surface-area increasing components, advantages
in terms of cost reduction of the aircraft interior panel material are obtained.
According to the invention of claim 4, because balsa wood, which is inexpensive and
easy to handle in terms of disposal and recycling, is used as the core member, advantages
in terms of requirements of cost reduction, strength, rigidity, flame retardancy,
and weight reduction being satisfied and environmental impact being reduced are obtained.
According to the invention of claim 5, because the surface-area increasing components
are provided, the surface area of the plate member to be impregnated with the flame
retardant is increased and advantages in terms of securing greater flame retardancy
are obtained. In addition, advantages in terms of further weight reduction of the
interior components of an aircraft are obtained by reducing the weight of the aircraft
interior panel material.
According to the invention of claim 6, because the adhesion area between the surface
members and the plate member is increased, the adhesive strength between the surface
members and the plate member is increased and advantages in terms of securing the
strength of the aircraft interior panel material are obtained.
According to the invention of claim 7, the surfaces of the plate member can be impregnated
in a short period of time. As a result, advantages in terms of increasing productivity
while maintaining high flame retardancy can be obtained.
Brief Description of Drawings
[0009]
- FIG. 1
- is a perspective view of an aircraft interior panel material of a first embodiment.
- FIG. 2
- is a cross-sectional view of the aircraft interior panel material of the first embodiment.
- FIG. 3
- is a perspective view illustrating a flame retardant being sprayed on a plate member
composing a core member according to the first embodiment.
- FIG. 4
- is an explanatory view illustrating the plate member composing the core member being
immersed in the flame retardant according to the first embodiment.
- FIG. 5
- is an explanatory view illustrating the plate member composing the core member being
immersed in the flame retardant and the flame retardant being pressurized according
to the first embodiment.
- FIG. 6
- is a perspective view of an aircraft interior panel material of a second embodiment.
- FIG. 7A
- is a cross-sectional view of the aircraft interior panel material of the second embodiment;
FIG. 7B is an explanatory view illustrating the resin, with which the surface members
are impregnated, melted and bonded to surface-area increasing components.
- FIG. 8
- is a perspective view of an aircraft interior panel material of a third embodiment.
- FIG. 9
- is a cross-sectional view of the aircraft interior panel material of the third embodiment.
- FIG. 10
- is a perspective view of an aircraft interior panel material of a fourth embodiment.
- FIG. 11
- is a cross-sectional view of the aircraft interior panel material of the fourth embodiment.
- FIG. 12
- is an explanatory view showing the experiment results of a first experiment.
- FIG. 13
- is an explanatory view showing the experiment results of a second experiment.
Description of Embodiments
First Embodiment
[0010] Next, an aircraft interior panel material 10A of the first embodiment is described
with reference to FIGS. 1 to 5.
"Aircraft interior panel material" broadly refers to a panel material such as a panel
material that composes an aircraft lavatory unit, a panel material that composes a
galley, a panel material that composes a luggage compartment, and the like.
As illustrated in FIG. 1, the aircraft interior panel material 10A includes a core
member 12, and surface members 14 attached to both surfaces of the core member 12.
The core member 12 includes a plate member 12A composed of balsa wood and having a
rectangular shape and uniform thickness. Both surfaces of the plate member 12A in
the thickness direction are flat surfaces.
Note that the size of a single plate made from a single piece of timber is limited,
and so the plate member 12A is constituted by a combination of single plates.
More specifically, single plates 1202 formed in an elongated shape are lined up in
the width direction to form the plate member 12A to a desired size. In addition, as
well as lining up the single plates 1202 in the width direction, the single plates
1202 may also be layered in the thickness direction to form the plate member 12A to
a desired thickness. In such a case, adjacent single plates 1202 may be adhered together
at end surfaces thereof by adhesive, and layered single plates 1202 may be adhered
together at side surfaces thereof by adhesive.
Balsa wood is light weight and strong and can be easily machined due to its softness.
Moreover, balsa wood is a natural material, which means that it is easy to handle
in terms of disposal and recycling, therefore assisting in environmental impact reduction.
From the perspective of obtaining a good strength-to-weight ratio, the specific gravity
of the balsa wood used is preferably from 0.090 to 0.26, both inclusive, and more
preferably from 0.090 to 0.10, both inclusive.
In addition, from the perspective of enhancing strength, the balsa wood is preferably
used with the surfaces perpendicular to the grain of the plate (end grain surfaces)
as the surfaces of the core member 12 on which the surface members 14 are disposed.
[0011] As illustrated in FIG. 2, both surfaces of the plate member 12A in the thickness
direction are impregnated with flame retardant 18, which reduces the flammability
of the balsa wood.
Known flame retardants for wood such as phosphoric acid based, boric acid based, silicic
acid based, aluminum based, and iron based flame retardants can be used as the flame
retardant 18.
Various methods of impregnating both surfaces of the plate member 12A in the thickness
direction with the flame retardant 18 can be considered.
For example, a sprayer 2 may be used to spray the flame retardant 18 on both surfaces
of the plate member 12A, as illustrated in FIG. 3, or the flame retardant 18 may be
applied to both surfaces of the plate member 12A.
Alternatively, the plate member 12A may be immersed in the flame retardant 18 inside
a container 4, as illustrated in FIG. 4.
As another alternative, as illustrated in FIG. 5, the plate member 12A, upon being
immersed in the flame retardant 18 in a container 6, may be subjected to static pressure
larger than the pressure (water pressure) at the depth where the plate member 12A
is immersed, or cycles of static pressure larger than the pressure (water pressure)
at the depth where the plate member 12A is immersed. By subjecting the plate member
12A to pressure larger than the pressure at the depth where the plate member 12A is
immersed, the surfaces of the plate member 12A can be impregnated in a short period
of time. As a result, advantages in terms of increasing productivity while maintaining
high flame retardancy are obtained.
[0012] As illustrated in FIGS. 1 and 2, the surface members 14 have the same shape and dimensions
as the plate member 12A and are disposed adhered to both surfaces of the plate member
12A in the thickness direction.
Fiber-reinforced composite material may be used as the surface members 14. As such
a fiber-reinforced composite material, a sheet-like prepreg composed of glass/aramid/carbon
fabric or fiber that has been impregnated with phenolic resin or epoxy resin may be
used.
In addition, the surface members 14 are attached to both surfaces of the plate member
12A in the thickness direction by: layering the surface members 14 on both surfaces
of the plate member 12A in the thickness direction, and then applying pressure and
heat to the surface members 14, thereby causing the resin with which the surface members
14 have been impregnated to thermally cured and adhering the surface members 14 to
both surfaces of the plate member 12A in the thickness direction.
[0013] According to the aircraft interior panel material 10A of the present embodiment,
because balsa wood, which is both light weight and strong and easily machined due
to its softness, is used as the core member 12, great advantages in terms of weight
reduction of interior components of an aircraft, such as aircraft lavatory units,
galleys, luggage compartments, and the like, are obtained.
In addition, because balsa wood, which is inexpensive and easy to handle in terms
of disposal and recycling, is used as the core member 12, advantages in terms of both
reducing the cost of the interior components of an aircraft and the environmental
impact are obtained.
In addition, because the surfaces of the plate member 12A are impregnated with the
flame retardant 18, advantages in terms of ensuring the high flame retardancy of the
interior components of an aircraft are obtained.
Second Embodiment
[0014] Next, an aircraft interior panel material 10B of the second embodiment is described
with reference to FIGS. 6 and 7A, 7B.
In this embodiment, components identical to those of the first embodiment are assigned
identical reference numerals, and detailed descriptions thereof are omitted.
Note that in the following embodiment, the configuration of the core member 12 is
different from that of the first embodiment, and the configurations of the components
other than the core member 12 are similar to those of the first embodiment.
In the second embodiment, a plurality of surface-area increasing components 16 are
provided in the plate member 12A that composes the core member 12. The surface-area
increasing components 16 are recessed from the surfaces of the plate member 12A to
increase the surface area thereof.
In the present embodiment, each of the surface-area increasing components 16 is constituted
by a hole 1602 that passes through the plate member 12A in the thickness direction.
The form of the hole 1602 in the plate member 12A is made using a machining tool such
as a drilling machine, for example.
In addition, as illustrated in FIG. 7A, both surfaces of the plate member 12A in the
thickness direction and the inner circumferential surfaces of the holes 1602 are impregnated
with the flame retardant 18, which reduces the flammability of the balsa wood.
The method of impregnating the plate member 12A with the flame retardant 18 and the
attachment of the surface members 14 to the plate member 12A are similar to that of
the first embodiment.
According to the aircraft interior panel material 10B of the second embodiment, a
similar effect as that of the first embodiment is obtained. As well as this effect,
advantages in terms of securing greater flame retardancy are obtained because the
surface area of the plate member 12A impregnated with the flame retardant 18 is increased.
In addition, advantages in terms of further weight reduction of the interior components
of an aircraft are obtained by providing a plurality of surface-area increasing components
16 for the purpose of reducing weight of the aircraft interior panel material 10B.
In addition, because the surface-area increasing components 16 (holes 1602) are recessed
from the surfaces of the plate member 12A, the adhesion area therebetween increases.
This is because in the case of the surface members 14, each constituted by a sheet-like
prepreg, being layered on both surfaces of the plate member 12A in the thickness direction
then the surface members 14 being adhered to both surfaces of the plate member 12A
in the thickness direction by applying pressure and heat, the resin with which the
surface members 14 have been impregnated melts and bonds to the surface of the plate
member 12A and the surface-area increasing components 16 (holes 1602). Resin with
which the surface members 14 have been impregnated in the state of being melted and
bonded to the surface-area increasing components 16 (holes 1602) is illustrated in
FIG. 7B by hatching and the reference sign 17. As a result of this configuration,
the adhesive strength between the surface members 14 and the plate member 12A is enhanced
and advantages in terms of ensuring the strength of the aircraft interior panel material
10B are obtained.
Third Embodiment
[0015] Next, an aircraft interior panel material 10C of the third embodiment is described
with reference to FIGS. 8 and 9.
In the third embodiment, the configuration of the surface-area increasing component
16 is different from that of the second embodiment, and the configurations of the
components other than the surface-area increasing component 16 are similar to those
of the second embodiment.
Specifically, the surface-area increasing component 16 is constituted by a recessed
portion 1604 with a closed bottom that has depth in the thickness direction of the
plate member 12A.
The recessed portion 1604 may be formed on only one surface of the plate member 12A
in the thickness direction or may be formed on both surfaces in the thickness direction.
The form of the recessed portion 1604 in the plate member 12A is made using a machining
tool such as a drilling machine, for example.
Both surfaces of the plate member 12A in the thickness direction and the inner circumferential
surfaces and bottom surfaces of the recessed portions 1604 are impregnated with the
flame retardant 18, which reduces the flammability of the balsa wood.
The method of impregnating the plate member 12A with the flame retardant 18 and the
attachment of the surface members 14 to the plate member 12A are similar to those
of the first embodiment.
According to the aircraft interior panel material 10C of the third embodiment, a similar
effect as that of the second embodiment is obtained. In addition, because the surface-area
increasing components 16 (recessed portions 1604) are recessed from the surfaces of
the plate member 12A, the adhesion area therebetween increases. This is because in
the case of the surface members 14, each constituted by a sheet-like prepreg, being
layered on both surfaces of the plate member 12A in the thickness direction then the
surface members 14 being adhered to both surfaces of the plate member 12A in the thickness
direction by applying pressure and heat, the resin with which the surface members
14 have been impregnated melts and bonds to the surface of the plate member 12A and
the surface-area increasing components 16 (recessed portions 1604). As a result of
this configuration, the adhesive strength between the surface members 14 and the plate
member 12A is enhanced and advantages in terms of ensuring the strength of the aircraft
interior panel material 10C are obtained.
Fourth Embodiment
[0016] Next, an aircraft interior panel material 10D of the fourth embodiment is described
with reference to FIGS. 10 and 11.
In the fourth embodiment, the configuration of the surface-area increasing component
16 is different from those of the second and third embodiments, and the configurations
of the components other than the surface-area increasing component 16 are similar
to those of the second and third embodiments.
Specifically, the surface-area increasing component 16 is constituted by grooves 1610
formed extending in both surfaces of the plate member 12A in the thickness direction.
The form of the grooves 1610 in the plate member 12A is made using a machining tool
such as a milling machine, for example.
Both surfaces (outer surfaces) of the plate member 12A in the thickness direction
and the surface of the plurality of grooves 1610 are impregnated with the flame retardant
18, which reduces the flammability of the balsa wood.
Both surfaces of the plate member 12A in the thickness direction and the surface of
the grooves 1610 are impregnated with the flame retardant 18, which reduces the flammability
of the balsa wood.
The method of impregnating the plate member 12A with the flame retardant 18 and the
attachment of the surface members 14 to the plate member 12A are similar to those
of the first embodiment.
[0017] Note that in the fourth embodiment, as illustrated in FIG. 11, the grooves 1610 formed
extending in one surface of the plate member 12A in the thickness direction that faces
a surface member 14 are offset from the grooves 1610 formed extending in the other
surface in a manner such that the grooves 1610 are located alternating in position
in the direction perpendicular to the extension direction the grooves 1610. Consequently,
advantages in terms of maintaining uniform thickness and strength of the core member
12 are obtained.
[0018] According to the aircraft interior panel material 10D of the fourth embodiment, a
similar effect as those of the second and third embodiments is of course obtained.
In addition, advantages in terms of cost and machining time reduction are obtained
compared to the case, such as in the second and third embodiments, in which a drilling
machine is used to form the holes 1602 or recessed portions 1604 in the plate member
12A because a milling machine can be used to form the grooves 1610 in the plate member
12A in a short period of time.
In addition, because the surface-area increasing components 16 (grooves 1610) are
recessed from the surfaces of the plate member 12A, the adhesion area therebetween
increases. This is because in the case of the surface members 14, each constituted
by a sheet-like prepreg, being layered on both surfaces of the plate member 12A in
the thickness direction then the surface members 14 being adhered to both surfaces
of the plate member 12A in the thickness direction by applying pressure and heat,
the resin the surface members 14 have been impregnated melts and bonds to the surface
of the plate member 12A and the surface-area increasing components 16 (grooves 1610).
As a result of this configuration, the adhesive strength between the surface members
14 and the plate member 12A is enhanced and advantages in terms of ensuring the strength
of the aircraft interior panel material 10D are obtained.
[0019] Note that in the description of the second to fourth embodiments, the surface-area
increasing component 16 constituted by any one of: the hole 1602, the recessed portion
1604, and the groove 1610 is described. However, the surface-area increasing components
16 may be constituted by any one of the hole 1602, the recessed portion 1604, and
the groove 1610 or by a combination thereof.
[0020] Next, experiment results relating to the aircraft interior panel material of the
present embodiment is explained.
A first experiment and second experiment were performed as described below.
The first experiment was a flammability test for the case in which the surfaces of
the plate member 12A were impregnated with the flame retardant by immersing the plate
member 12A in a solution of the flame retardant and applying no pressure load to the
plate member 12A.
The second experiment was a flammability test for the case in which the surfaces of
the plate member 12A were impregnated with the flame retardant by immersing the plate
member 12A in a solution of the flame retardant then applying a large water pressure
to the solution.
First Experiment
[0021] In the first experiment, sample aircraft interior panel materials 10A according to
the first embodiment were manufactured as described below. The samples were tested
via the vertical flammability test (hereafter referred to as "F1 test") for 60 seconds
as specified in the Federal Aviation Regulations (FAR) 25.853 Appendix F Part I (a)(i).
The results of the aircraft interior panel materials 10A satisfied the flame retardancy
requirements.
Passing requirements for the F1 test was a self-extinguishing time of 15 seconds or
less, a burn length of 6 inches or less, and flaming time of drippings of 3 seconds
or less.
The manufactured aircraft interior panel materials 10A were configured as follows.
Rectangular plate-like plate members 12A 31 x 8 cm in size, 1 cm thick, and with a
specific gravity of approximately 0.1 were immersed in solutions of boric acid based
flame retardant of different concentrations for 24 hours, thereby impregnating the
surfaces of the plate members 12A with the flame retardant. The resulting specific
gravity of the core members 12 was from 0.11 to 0.16, both inclusive.
[0022] Next, the above-described flammability test is described in detail.
Specific gravity of plate member 12A prior to treatment: 0.098
Plate member 12A trade name: BALTEK® SB (SB.50)
Plate member 12A manufacturer: 3A Composites
Flame retardant 18 trade name: Fireless B®
Flame retardant 18 manufacturer: TRUST LIFE CORPORATION
Core member 12 treatment method after immersion in solution of flame retardant 18
of each concentration: Dried at room temperature
[0023] In the flammability test described above, as illustrated in FIG. 12, the concentration
of the flame retardant 18 was varied to manufacture the flammability test samples
of Test Example 1 to 3.
Note that the flammability test samples are each constituted by the core member 12
impregnated with the flame retardant 18 described above, and the surface members 14
described below adhered to both surfaces of the core member 12.
Surface members 14: Glass/phenolic prepreg
As indicated in FIG. 12, the Test Examples 1, 2, and 3 passed the F1 test.
Second Experiment
[0024] In the second experiment, sample aircraft interior panel materials 10A according
to the first embodiment were manufactured under the immersion conditions described
below. The samples were tested via the F1 test in a similar manner to that of the
first experiment. The results of the aircraft interior panel materials 10A satisfied
the flame retardancy requirements. The manufactured aircraft interior panel materials
10A were configured as follows.
[0025] Rectangular plate-like plate members 12A 31 x 8 cm in size, 1 cm thick, and with
a specific gravity of approximately 0.1 were immersed in a solution of boric acid
based flame retardant of 10 wt% concentration under the immersion conditions described
below, thereby impregnating the surfaces of the plate members 12A with the flame retardant.
The resulting specific gravity of the core members 12 was approximately 0.11.
The details of the above-described flammability test are similar to that of the first
experiment.
In the flammability test described above, as illustrated in FIG. 13, the immersion
conditions were varied to manufacture the flammability test samples of Test Example
4 to 6.
Note that the flammability test samples, in a similar manner to that of the first
experiment, are each constituted by the core member 12 impregnated with the flame
retardant 18 described above, and glass/phenolic prepreg surface members 14 adhered
to both surfaces of the core member 12.
[0026] Immersion conditions were as follows.
Test Example 4: As illustrated in FIG. 5, the plate member 12A was immersed in the
flame retardant 18 inside the container 6, and water pressure of 50 kPa was applied
for 5 minutes. Then, the loaded water pressure was removed for 1 minute. This cycle
was repeated for 4 hours. Test Example 5: The plate member 12A was immersed in the
flame retardant 18 inside the container 6, and water pressure (static pressure) of
50 kPa was applied for 4 hours.
Test Example 6: The plate member 12A was immersed in the flame retardant 18 inside
the container 6, and water pressure (static pressure) of 100 kPa was applied for 2
hours.
As indicated in FIG. 13, the Test Examples 4, 5, and 6 passed the F1 test. It is clear
from the results that by immersing the plate member 12A in a solution of the flame
retardant 18 and then applying a large water pressure to the solution, the surfaces
of the plate member 12A can be impregnated with the flame retardant 18 in a short
period of time (approximately 2 to 4 hours), resulting in advantages in terms of increasing
productivity while maintaining the flame retardancy of the aircraft interior panel
material 10A.
Reference Signs List
[0027]
10A, 10B, 10C, 10D Aircraft interior panel material
12 Core member
12A Plate member
14 Surface member
16 Surface-area increasing component
1602 Hole
1604 Recessed portion
1610 Groove
18 Flame retardant